Potentiels évoqués auditifs du tronc cérébral et enregistrement dynamique du réflexe stapédien: variations interindividuelles

Quantification of the stapedial reflex reveals delayed responses in autism

Autism is a developmental disorder characterized, in part, by sensory abnormalities. It is well established that most if not all patients with autism have problems with auditory processing, ranging from deafness to hyperacusis, and physiological testing of auditory function (i.e. auditory brain stem responses) implicates brain stem dysfunction in autism. Additionally, previous research from this lab has revealed significantly fewer auditory brain stem neurons in autistic subjects as young as 2 years of age. These observations have led us to hypothesize that objective, noninvasive measures of auditory function can be used as an early screening tool to identify neonates with an elevated risk of carrying a diagnosis of autism. Here, we provide a detailed quantitative investigation of the acoustic stapedial reflex (ASR), a three- or four-neuron brain stem circuit, in young autistic subjects and normal developing controls. Indeed, we find significantly lower thresholds, responses occurring at significantly longer latency and right-left asymmetry in autistic subjects. The results from this investigation support deficits in auditory function as a cardinal feature of autism and suggest that individuals with autism can be identified by their ASR responses.

Brain-stem auditory evoked response (BAER): normative study in children and adults

The influences of age and sex on the BAER latency values are analysed in a non-clinical sample of adults and children. We found (1) that BAER values vary according to age and sex, but for the III-V interpeak latency (IPL); (2) that the age effect is more important than the sex effect on absolute latency (AL) II, III and V; (3) that there is a significant sex effect on the I-III IPL. Comparisons to other studies are made: we find differences but no contradiction. This is briefly discussed.